Sacrificial Collar

ABSTRACT

A sacrificial collar that is placed on a structural component to protect against stray current or galvanic corrosion. The collar includes an upper section having a half-circle cavity, and a corresponding lower section having a half-circle cavity. When the two sections are mated, the two cavities together create a single circular opening. The two sections are placed on a structural component, with the component secured between the sections, in the opening. Attachment means, preferably in the form of a bolt and nut combination are utilized to attach the two sections together and secure the collar on the structural component. Once secured, the sacrificial collar is subjected to stray current or galvanic corrosion, thereby causing the collar to deteriorate, instead of the structural component being subjected to stray current or galvanic corrosion which would cause the component to deteriorate and would destroy the component.

TECHNICAL FIELD

The invention generally pertains to structure components, and moreparticularly to a sacrificial collar that is placed on an underwaterstructural component of a sea vessel to protect against stray current orgalvanic corrosion.

BACKGROUND ART

Two of the most significant problems that affect submerged components ofa sea/water vessel are stray current corrosion and galvanic corrosion.Stray current corrosion is a serious destructive occurrence and resultsfrom a metal with an electrical current flowing into it submerged inwater that is grounded, such as a lake, river or ocean. The current canleave the metal and flow through the water to ground. This will causerapid deterioration of the metal at the point where the current leaves.Stray direct current is particularly destructive.

Galvanic corrosion (also called “dissimilar metal corrosion”) refers tocorrosion damage induced when two dissimilar materials are coupled in acorrosive electrolyte. The corrosion occurs when two (or more)dissimilar metals are brought into electrical contact usually underwater. When a galvanic couple forms, one of the metals in the couplebecomes the anode and corrodes faster than it would by itself, while theother becomes the cathode and corrodes slower than it would alone.Either (or both) metal in the couple may or may not corrode by itself.When contact with a dissimilar metal is made, however, theself-corrosion rates will change. Corrosion of the anode will accelerateand corrosion of the cathode will decelerate or even stop.

The major cause for corrosion is a potential difference between thedifferent materials. The bimetallic driving force was discovered in thelate part of the eighteenth century by Luigi Galvani in a series ofexperiments with the exposed muscles and nerves of a frog thatcontracted when connected to a bimetallic conductor. The principle waslater put into a practical application by Alessandro Volta who built in1800, the first electrical cell, or battery, a series of metal disks oftwo kinds, separated by cardboard disks soaked with acid or saltsolutions. This is the basis of all modern wet-cell batteries, and itwas a tremendously important scientific discovery, because it was thefirst method found for the generation of a sustained electrical current.

One of the most prevalent problems associated with stray current orgalvanic corrosion is the deterioration of submerged structuralcomponents on sea vessels. This is especially pronounced on componentsthat are made of a soft metal, which will deteriorate more quickly thancomponents made of a hard metal. In addition to the cost incurred toreplace or fix damaged/destroyed components, there is also a significantsafety risk that occurs when certain components are damaged/destroyed.

The corrosion potential of any metal is a voltage that can be measuredby a reference electrode. Such measurements in water commonly are madewith a silver/silver chloride reference electrode. The corrosionpotential is a characteristic value for that metal, and it does matterif you have one metal component or 100, the corrosion potential staysthe same.

There have been attempts to address the problem of stray current orgalvanic corrosion. The most common solution is to add what is typicallyreferred to as a sacrificial anode. The anodes are made of a metal thatwill attract electrolytes faster than a metal to which it is attached,thereby causing the anode to experience the destructive impact. Whileprior art sacrificial anodes are usually effective, many of the designsare not entirely practical and can be difficult to implement.

What is needed is a sacrificial anode that can be quickly and easilyattached, and that will protect any structural component to which it isattached. Optimally, a sacrificial collar design, as disclosed herein,would be provided. A collar design would be easy to attach could bemanufactured in a variety of shapes and sizes for use on many types ofcomponents both submerged in seawater and in other environments.

A search of the prior art did not disclose any literature or patentsthat read directly on the claims of the instant invention. However, thefollowing U.S. patents are considered related:

PAT. NO. INVENTOR ISSUED 3,024,183 MacEwan Mar. 6, 1962 3,152,059Wellington Oct. 6, 1964 4,391,567 Ciampolillo Jul. 5, 1983

The U.S. Pat. No. 3,024,183 discloses a method producing sacrificial orconsumable zinc anodes for use in inhibiting corrosion by galvanicaction, and sacrificial zinc anodes that are use for the protection ofmetal structures and equipment such as heat exchangers, pipe lines, shiphulls, storage tanks and the like. In some instances, anodes are made inthe form of cast blocks or slabs, with steel inserts to provideelectrical contact between the anode and the metal structure to beprotected, and also to provide means for fastening the anode to themetal structure to be protected.

The U.S. Pat. No. 3,152,059 discloses a method of making sacrificial orconsumable zinc anodes for use in inhibiting corrosion by galvanicaction and sacrificial zinc anodes produced for the protection fromcorrosion of metal structures and equipment such as heat exchangers,pipe lines, ships' hulls, storage tanks and the like. Sacrificial orconsumable anodes are made in the form of cast blocks or slabs withsteel inserts to provide electrical contact between the anode and themetal structure to be protected and, also, to provide means forfastening the anode to the structure.

The U.S. Pat. No. 4,391,567 discloses a corrosion preventing device formounting in seawater on an electrically conductive propeller shaftsupporting a marine propeller composed of a metal having a firstgalvanic potential. The device includes an annular washer having agenerally circular periphery, composed of a metal having a secondgalvanic potential not greater than the first galvanic potential. Thedevice further includes a generally toroidal anode having a circularperiphery concentric with the axis, composed of a metal having a thirdgalvanic potential greater than the first galvanic potential. Thegalvanic cell formed by the washer cathode and the toroidal anodemaintains the propeller at a relative cathodic potential, therebypreventing the corrosion thereof in the seawater.

For background purposes and indicative of the art to which the inventionrelates, reference may be made to the following remaining patents foundin the patent search.

PAT. NO. INVENTOR ISSUED D474,161 M.ang.nsson et al May 6, 20033,956,095 Khoo et al May 11, 1976 3,994,794 Bohne Nov. 30, 19764,190,512 Wyatt et al Feb. 26, 1980 4,409,081 Terrase Oct. 11, 19839,045,834 Lambourne Jun. 2, 2015

DISCLOSURE OF THE INVENTION

In its basic design the sacrificial collar is comprised of a firstsection having a half-circle cavity and a matching second section havinga half-circle cavity. The collar is preferably square or rectangular butcan be any geometric shape, and is made of metal such as zinc, aluminumor magnesium, with zinc currently preferred. The first section and thesecond section are secured together around a structural component, withthe component located within the cavities on the two sections.Typically, the structural component will be located on an environmentwhere galvanic corrosion occurs such as within seawater. Therefore, thesacrificial collar is especially effective for use on sea vesselcomponents that are submerged in seawater. Although this is the primaryuse, the sacrificial collar can also be utilized in other environmentswhere corrosion can occur.

Once the two sections are secured together and onto a structuralcomponent, the sacrificial collar will attract the stray current orgalvanic corrosion, instead of the stray current or galvanic corrosionbeing subjected to the structural component. The sacrificial collar willliterally sacrifice itself to the stray current or galvanic corrosion,thereby protecting the structural component to which the collar issecured.

In view of the above disclosure, the primary object of the invention isto provide a sacrificial collar that is secured on a structuralcomponent to protect the component against stray current or galvaniccorrosion.

In addition to the primary object, it is also an object of the inventionto provide a sacrificial collar that:

-   -   is easy to secure,    -   is durable,    -   can be made in various shapes and sizes,    -   can be used on different types of structural components,    -   can lower insurance costs,    -   can increase safety,    -   can be sold as an OEM product or as an after-market product,    -   is user installable,    -   will not interfere with the operation or function of a component        to which it is secure, and    -   is cost effective from both a manufacturer's and consumer's        point of view.

These and other objects and advantages of the present invention willbecome apparent from the subsequent detailed description of thepreferred embodiment and the appended claims taken in conjunction withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an orthographic front view of a sacrificial collar with anupper section and a lower section attached together by bolt and nutcombinations.

FIG. 2 is an orthographic side view of the sacrificial collar with theupper section and the lower section separated.

FIG. 3 is an elevational side view of the sacrificial collar secured ona structural component consisting of a shaft.

FIG. 4 is an orthographic front view of the sacrificial collar withcorner cut-outs to allow an element such as seawater to freely pass overand across the collar.

FIG. 5 is an elevational side view of an oblong shaped sacrificialcollar.

FIG. 6 is an orthographic front view of the sacrificial collar withattachment means in the form of a resilient band.

BEST MODE FOR CARRYING OUT THE INVENTION

The best mode for carrying out the invention is presented in terms thatdisclose a preferred embodiment of a sacrificial collar. Two of the mostserious problems associated with the use of metal components are; first,stray current corrosion, and second, galvanic corrosion which is alsoknown as bimetallic corrosion or dissimilar metal corrosion. Theseproblems are especially prevalent for metal components that are locatedin seawater, such as submerged parts of a boat or other sea vessel.

Stray current corrosion occurs when metal with an electrical currentflowing into it is immersed in water that is grounded (such as in anylake, river or ocean). The current can leave the metal and flow throughthe water to ground. This will cause rapid corrosion of the metal at thepoint where the current leaves. Stray direct current is particularlydestructive. Stray current corrosion can cause rapid deterioration ofthe metal. If the metal happens to be aluminum, it can be destroyed in amatter of days.

Galvanic corrosion occurs when there are two different metals arephysically or electrically connected and immersed in seawater,effectively creating a battery. Some amount of current flows between thetwo metals, and the electrons that make up that current are supplied byone of the metals giving up bits of itself in the form of metal ions tothe seawater. The most common casualty of galvanic corrosion is a bronzeor aluminum propeller on a stainless steel shaft, but metal struts,rudders, rudder fittings, outboards, and stern drives are also at risk.An example of this is a ship propeller that is made of bronze and zinc.When corrosion occurs the zinc in the propeller will deteriorate first,leaving zinc molecules in the bronze, which results in the remainingbronze being extremely fragile.

The way to counteract stray current or galvanic corrosion is to add athird metal into the circuit, one that is quicker than the other two togive up its electrons. The instant sacrificial collar can function asthe third metal. While the sacrificial collar is predominantly used inseawater applications, there are instances of corrosion occurring inother locations. The design of the sacrificial collar allows the collarto be effectively utilized in many of these other instances.Additionally, the sacrificial collar can be secured on many types ofstructural components. For the purpose of this disclosure, thesacrificial collar is disclosed and shown secured on a circular objectsuch as a shaft. Any modifications that would be necessary to facilitatethe use of the sacrificial collar on other sizes/shapes of structuralcomponents is anticipated and thereby intended to be covered by thisdisclosure.

The sacrificial collar 10, as shown in FIGS. 1-6, can be made of variousmetals including zinc, aluminum or magnesium, with zinc currentlypreferred. The metal utilized for the sacrificial collar is specificallychosen due to the metal's ability to attract the stray current orgalvanic corrosion that would otherwise affect the structuralcomponent(s). The sacrificial collar 10 can be any shape, but for thepurpose of this disclosure a rectangular sacrificial collar 10 isprimarily described and shown, along with an oblong sacrificial collarfor reference.

As shown in FIGS. 1-4, the sacrificial collar 10 is comprised of asquare or rectangular upper section 12 with a front surface 14, a rearsurface 16, a right surface 18, a left surface 20, an upper surface 22,and a lower surface 24. Extending along the collar surface 24 is ahalf-circle cavity 28, and extending through one of at least twoangularly opposed corners of the upper section from the upper surface tothe lower surface is a bore 34.

A square or rectangular lower section 42 is a mirror image of the uppersection 12, and is also comprised of a front surface 44, a rear surface46, a right surface 48, a left surface 50, an upper surface 52 and alower surface 54. Extending along the upper surface 52 is a half-circlecavity 58. It should be noted that the half-circle cavities 28,58 areonly one possible shape. Other shapes such as square or triangular canalso be utilized depending on the requirements of theapplication/function.

When the upper section 12 is mated to the lower section 42 the tworespective half-circle cavities 28,58 create a single circular opening60 that extends through the sacrificial collar 10 from the frontsurfaces 14,44 to the rear surfaces 16,46. Extending through one of atleast two angularly opposed corners of the lower section 42 from thelower surface 54 to the upper surface 52 is a bore 64. The bores 34 onthe upper section 12 are aligned with the bores 64 on the lower section42.

The sacrificial collar 10 is secured on a circular structural componentsuch as a shaft 86 by placing the upper section 12 on the shaft 86 suchthat one-half of the shaft's diameter is within the upper section'scavity 28 and then placing the lower section 42 on the shaft 86 suchthat the other half of the shaft's diameter is within the lowersection's cavity 58. The sacrificial collar's two sections 12,42 arethen secured on the shaft 86 by attachment means 70 that preferablycomprise inserting a bolt 72 into each of the bores 34,64 and screwing anut on the end of the bolt. Once the nut is tightened on the bolt, thetwo sections 12,14 are secured on the shaft 80, as shown in FIG. 3. Oncesecured, the sacrificial collar is subjected to stray current orgalvanic corrosion thereby causing the collar 10 to deteriorate, insteadof the shaft 80 (or other structural components to which the collar issecured) being subjected to stray current or galvanic corrosion whichwould cause the shaft 86 to deteriorate and would destroy the shaft 86.

In addition to the bolt and nut combination 72, the attachment means 70for attracting the upper section 12 to the lower section 42, and thatfacilitates the securing the sacrificial collar 10 on a structuralcomponent, can be comprised of a screw 74, as shown in FIG. 1, that isinserted through at least one bore on the upper section and tightenedinto at least one corresponding tapped bore on the lower section 42.

Also, as shown in FIG. 6, the attachment means 70 can be comprised of atleast one resilient band 76 that is placed around the upper and lowersections 12,42. The resiliency of the band 76 allows the band tomaintain continuous and constant pressure on the sacrificial collar 10even as the collar corrodes and deteriorates. As shown in FIG. 4, thesacrificial collar 10 can also include angular cut-outs 78 at eachcorner. The cut-outs 78 allow an element, such as seawater, to morefreely pass over and across the sacrificial collar 10.

As previously disclosed, the sacrificial collar 10 is preferably squareor rectangular, as shown in FIGS. 1-4. The collar 10 can also be othershapes such as circular or oblong 82, as shown in FIG. 5. The collar 10is especially effective for use on structural components that aresubmerged in seawater. In addition, the sacrificial collar can also beused with equal efficacy on other components or items, or in otherenvironments, including construction, water, oil, gas, liquid pipes,rebar protection, water heaters, heat exchangers, plumbing andunderground utilities.

While the invention has been described in detail and pictorially shownin the accompanying drawings it is not to be limited to such details,since many changes and modification may be made to the invention withoutdeparting from the spirit and the scope thereof. Hence, it is describedto cover any and all modifications and forms which may come within thelanguage and scope of the claims.

Parts List 10 Sacrificial Collar 12 Upper Section 14 Front Surface 16Rear Surface 18 Right Surface 20 Left Surface 22 Upper Surface 24 LowerSurface 26 28 Half Circle Cavity 30 32 34 Bore 36 38 40 42 Lower Section44 Front Surface 46 Rear Surface 48 Right Surface 50 Left Surface 52Upper Surface 54 Lower Surface 56 58 Half Circle Cavity 60 Opening 62 64Bore 66 68 70 Attachment Means 72 Bolt and Nut Combination 74 Screw 76Band 78 Cut-Out 80 82 Oblong 84 86 Shaft

1. A sacrificial collar that is placed on a structural component toprotect against stray current or galvanic corrosion, wherein saidsacrificial collar is comprised of a first section having a half-circlecavity and a second section having a half-circle cavity, wherein saidfirst section and said second section are secured together and onto astructural component by attachment means, wherein said sacrificialcollar is subjected to stray current or galvanic corrosion instead ofthe structural component to which said collar is secured being subjectedto stray current or galvanic corrosion, which would destroy thestructural component.
 2. The sacrificial collar as specified in claim 1wherein said sacrificial collar is made of a material selected from thegroup consisting of zinc, aluminum or magnesium.
 3. The sacrificialcollar as specified in claim 1 wherein said sacrificial collar issubstantially square.
 4. The sacrificial collar as specified in claim 1wherein the structural component is located in seawater.
 5. Thesacrificial collar as specified in claim 1 wherein the structuralcomponent is attached to a sea vessel.
 6. The sacrificial collar asspecified in claim 5 wherein the structural component is circular. 7.The sacrificial collar as specified in claim 1 wherein said sacrificialcollar is secured to the structural component by attachment means. 8.The sacrificial collar as specified in claim 7 wherein the attachmentmeans is comprised of at least two bolt and nut combinations, whereinone bolt extends through corresponding bores on said first section andsaid second section.
 9. A sacrificial collar that is placed on astructural component to protect against stray current or galvaniccorrosion, wherein said sacrificial collar is comprised of: a) a squareupper section with a front surface, rear surface, a right surface, aleft surface, an upper surface, and a lower surface, wherein extendingalong the lower surface is a half circle cavity, wherein extendingthrough one of at least two angularly opposed corners of said uppersection from the upper surface to the lower surface is a bore, and b) asquare lower section that is a mirror image of said upper section andcomprised of a front surface, a rear surface, a right surface, a leftsurface, an upper surface, and a lower surface, wherein extending alongthe upper surface is a half circle cavity, wherein when said uppersection is mated to said lower section the two respective half-circlecavities create a single circular opening that extends through saidsacrificial collar from the front surface to the rear surface, whereinextending through one of at least two angularly opposed corners of saidlower section from the lower surface to the upper surface is a bore,wherein the bores on said upper section are aligned with the bores onsaid lower section, wherein said sacrificial collar is secured onto acircular structural component by placing said upper section onto thestructural component such that one-half of the structural component'sdiameter is within said upper section's cavity and placing said lowersection onto the structural component's diameter such that the otherhalf of the structural component is within said lower section's cavity,wherein said sacrificial collar's two sections are secured onto thestructural component by inserting a bolt into each of the bores andscrewing a nut onto the end of the bolt wherein once the nut istightened onto the bolt, the two sections are secured on the structuralcomponent, wherein once secured, said sacrificial collar is subjected tostray current or galvanic corrosion thereby causing said collar todeteriorate, instead of the structural component to which said collar issecured subjected to stray current or galvanic corrosion which wouldcause the component to deteriorate and would destroy the component. 10.The sacrificial collar as specified in claim 9 wherein said sacrificialcollar is made of a material selected from the group consisting of zinc,aluminum or magnesium.
 11. The sacrificial collar as specified in claim9 wherein the structural component is located in seawater.
 12. Thesacrificial collar as specified in claim 9 wherein the structuralcomponent is attached to a sea vessel.
 13. The sacrificial collar asspecified in claim 9 wherein the structural component is circular. 14.The sacrificial collar as specified in claim 9 wherein said collar iscircular or oblong.
 15. The sacrificial collar as specified in claim 9wherein said collar is geometric shaped.
 16. The sacrificial collar asspecified in claim 9 wherein the attachment means further comprises ascrew that is inserted through at least one bore on said upper sectionand tightened into at least one corresponding tapped bore on said lowersection.
 17. The sacrificial collar as specified in claim 9 wherein theattachment means further comprise at least one resilient band that isplaced around said upper and lower sections, wherein the resiliency ofthe band allows the band to maintain continuous and constant pressure onsaid collar as said collar corrodes and deteriorates.
 18. Thesacrificial collar as specified in claim 9 further comprising angularcut-outs at each corner of said sacrificial collar, wherein the cut-outsallow an element to freely pass over and across said collar.
 19. Thesacrificial collar as specified in claim 18 wherein the element isseawater.